Known devices may be helpful in providing in-vivo sensing, such as imaging or pH sensing. Autonomous in-vivo sensing devices, such as swallowable or ingestible capsules or other devices, may move through a body lumen, sensing as they move along. An autonomous in-vivo sensing device such as an imaging device may include, for example, an imager for obtaining images from inside a body cavity or lumen, such as the gastrointestinal (GI) tract while the in-vivo imaging device passes through the GI lumen. The imager may, for example, be associated with an optical system, and optionally a transmitter and an antenna. Some of these devices use a wireless connection to transmit image data. Other devices, systems and methods for in-vivo sensing of passages or cavities within a body, and for sensing and gathering information (e.g., image information, pH information, temperature information, electrical impedance information, pressure information, etc.), are known in the art.
Viewing pathologies such as tumors, lesions or ulcers and the like may be complicated by the fact that the gastrointestinal tract and the item or pathology sought to be viewed have very similar background color.
Different methods exist for enhancing in vivo image contrast. One method is to render grayscale digital images in pseudocolor by assigning specific gray level ranges to particular color values. This technique is useful for highlighting particular regions of interest in grayscale images because the human eye is better able to discriminate between different shades of color than between varying shades of gray. Pseudocolor imaging is widely employed in fluorescence microscopy to display merged monochrome images obtained at different wavelengths utilizing multiply stained specimens. Often, the color assigned to individual fluorophore images in a collage assembly is close in color to that naturally emitted by the fluorescent dye.
Another technique for enhancement of vascular images is narrow-band imaging (NBI), which is an optical filter technology that improves the visibility of subtle tissue structures based upon the phenomenon that the depth of light penetration depends on its wavelength (shorter wavelength light, e.g., blue, penetrates only superficially, whereas longer wavelength light, e.g., red, penetrates into deeper layers). In one NBI system, white light is passed through a rotary red-green-blue filter to sequentially illuminate a mucosa with RGB illumination, and the reflected light is detected separately and integrated into a single color image by a video processor. In another NBI system, two discrete bands of light, one blue at 415 nm, and one green at 540 nm, are used. Narrow band blue light displays superficial capillary networks, while green light displays subepithelial vessels, and when combined they offer an extremely high contrast image of the tissue surface. For example, in an NBI image on a monitor, capilaries on the surface can be displayed in brown, and veins in the sub surface can be displayed in cyan.
In addition, FUJI Intelligent Color Enhancement (FICE), developed by Fujinon, Inc. of New Jersey, a wholly owned subsidiary of Fujinon Corporation of Saitama City, Japan, provides endoscopic diagnosis systems based on spectral estimation technology. In this system, a processor takes ordinary endoscopic images from the video processor and arithmetically processes, estimates and produces an image of a given, dedicated wavelength of light so as to enable clearer observation of tissue characterization on surface parts and of capillary orientations.